Method of killing arthropod pests and composition therefor



United States Patent METHOD OF KILLING ARTHROPOD PESTS AND COMPOSITEUNTHEREFOR Harry Bender, Torrance, Calif assignor to Stauifer ChemicalCompany, a corporation of Delaware No Drawing. Application June 19,1952, Serial No. 294,490

12 Claims. (Cl. 1167-40;

This patent application is a continuation-in-part of three patentapplications heretofore filed by me namely: Serial No. 224,679, filedMay 4, 1951; Serial No. 132,807, filed December 13, 1949, both nowabandoned, and Serial No. 105,273, filed July 16, 194-9.

The invention relates broadly to pest control materials and particularlyrelates to materials for killing arthropods such as insects, mites,ticks and spiders which belong to the classes Insecta and Arachnida. Ina more restricted sense the present invention relates to materials whichare miticides.

In my application Serial No. 105,273 I disclosed that 4-chlorophenylphenyl sulfone is effective in killing mites.

and in my application Serial No. 132,807 that 4-bromophenyl phenylsulfone was also effective for this purpose. In my application SerialNo. 224,679 I disclosed that 4-chlorophenyl phenyl sulfone had enhancedactivity if applied in admixture with diphenyl sulfone, with bis(4-chlorophenyl) sulfone or mixtures of these compounds.

I further disclosed that the bromo compounds could be substituted forthe chloro compounds. In addition, it was disclosed that certain of themixtures, hereinafter discussed in greater detail, have insecticidal aswell as miticidal activity.

Stated in other terms, the invention contemplates the use of 4-chlorophenyl phenyl sulfone or 4-bromophenyl phenyl sulfone as amiticide and the addition to either of these materials of eitherdiphenyl sulfone or bis(4- chlorophenyl) sulfone or mixtures of theselast two compounds. I shall first describe the use of 4-chlorophenylphenyl sulfone or 4-bromophenyl phenyl sulfone and shall then describethe even superior results which may be obtained by the use of thesesubstances in admixture with the other materials mentioned.

4-chlorophenyl phenyl sulfone and 4-bromophenyl phenyl sulfone areeffective in killing mites, particularly plant feeding mites belongingto the families Tetranychadae and Eriophyidae in all stages of theirdevelopment, e. g. eggs, and all mature and immature postembryonicforms.

The compounds have various advantages. For example, in comparison with0,0,diethy1-O,p-nitrophenyl thiophosphate (Parathion), 4-chlorophenylphenyl sulfone is more effective in controlling various species of mitesat the same concentration. In addition, 4-chlorophenyl phenyl sulfone isless phytotoxic than Parathionv and therefore can be used on a widerrange of plants and at higher concentrations to control mites than ispossible with Parathion. Reference has been made to Parathion forcomparison because it is presently regarded as a very effective miticideand is being used extensively on a commercial scale. The 4-chlorophenylphenyl sulfone and 4-bromophenyl phenyl sulfone are further unique inthat they are eifective against mites while closely related compoundsare not, such as the para-dichlorodiphenyl sulfone,ortho-monochlorodiphenyl sulfone, meta-monochlorodiphenyl sulfone,p-monofluorodiphenyl sulfone and p-monoiododiphenyl sulfone.

The 4-chlorophenyl phenyl sulfone and 4-bromophenyl phenyl sulfone canbe applied in any desired manner, as an aqueous spray, as an aerosol, oras a dust. When applied in an aqueous spray, the 4-chlorophenyl phenylsulfone or 4-bromophenyl phenyl sulfone should be present in aconcentration of from 0.01% to 1.0%; usually about 0.125 to 0.25% byweight. When applied as a dust, the 4-chlor0phenyl phenyl sulfone or the4-br0mophenyl phenyl sulfone should be present in concentration of 1% to50% by weight in a suitable inert carrier, usually about 5%. The4-chlorophenyl phenyl sulfone and 4-bromophenyl phenyl sulfone are notdifiicult to compound and one can employ these separately or as amixture in any of the carrier compositions utilized with acaricidesheretofore; they are solids at ordinary temperatures.

The following are illustrations of the effectiveness of the4-chlorophenyl phenyl sulfone.

Potted cotton plants heavily infested with all stages of the two-spottedmite, Tetranychus bz'maculatus (Harvey) were sprayed in groups of twowith various aqueous spray compositions containing 4-chlorophenyl phenylsulfone; the compositions were identical except that the concentrationsof 0.5%, 0.25%, 0.125%, 0.06% and 0.03% were employed. On all of theplants sprayed with these compositions, there was a 100% kill of eggsand all postembryonic forms. All plants remained free of mites fortwenty-one days thereafter, at which time the experiment was terminated.

The mite infestation on the unsprayed control plants: increased rapidlyand, at the termination of the experiment, their leaves had beendestroyed by the excessive injury caused by the mites.

To show the comparative effectiveness of 4-chlorophenyl phenyl sulfoneas against Parathion, under similar conditions potted cotton plants,infested with the twospotted mite, were sprayed with a conventionallyformulated Parathion aqueous spray containing 0.03% of Parathion. Thistest was conducted in every detail in an identical manner to the testswith 4-chlorophenyl phenyl sulfone. This Parathion spray caused a 100%mortality of all post-embryonic forms, but only 90% of the eggs. Themite population on these plants had increased appreciably by the timethe experiment was terminated because of the incomplete ovicidal actionof the Parathion.

To establish further the efiiectiveness of 4-chlo1'ophenyl phenylsulfone, field tests were conducted on the following species of mites onthe following hosts; in these tests an aqueous spray containing 0.125%of 4-chlorophenyl phenyl sulfone was employed:

European red mite, Paratetranychus pilosus, on prune. and apple; theclover mite, Bryobia praetiosa, on prune, peach, apple and almond; thepear leaf blister mite,

Eriophyes pyri, on prune. In all cases, excellent control The bulk ofthe productv (ap-. proximately distills over at 382-386 C. The;

cooled distillate melts around 82 C. This reaction product was useful inkilling mites, as illustrated by the following test:

Potted cotton plants and potted pinto bean plants heavily infested withT etranychus bimaculatus (Harvey) were sprayed with aqueous suspensionsof 4-chlorophenyl phenyl sulfone at concentrations of 0.5%, 0.25% and0.125% of compound by weight. The several compositions were made up froma wettable powder. Observations made twelve days after spraying plantsshowed a complete mortality of all ova and all active forms on cottonplants at all concentrations. Complete mortality of all ova and allactive forms occurred on all bean plants at concentrations of 0.5% and0.25 with several very weak adult survivors observed on plants sprayedat 0.125 concentrations. No potentially viable ova were observed on thepinto bean plants sprayed with 0.l25% concentrations. Controls remainedheavily infested and suffered severe injury due to the mites during thecontrol period.

Instead of passing the benzene vapor through the 4- chlorobenzenesulfonic acid in the above example, one can use the reverse procedure,that is, passing 4-chlorobenzol vapor through benzene sulfonic acid, theconditions otherwise being the same.

In the above procedures, :the reaction temperature of 230250 C. resultsin the evolution of sulfur dioxide. When the temperature is lowered toabout 160 C. and the reaction is carried on in accordance with thedirections given by Meyer, Annalen, vol. 433, pp. 327 et. seq. (1927),useful materials are also obtained upon reaction of 4- chlorobenzenesulfonic acid and benzene, or the reverse procedure, that is by reactingbenzene sulfonic acid and 4-chlorobenzol. All of these materials areuseful, as I have indicated.

As illustrative of compositions which can be effective acaricides, thefollowing compositions are set forth:

50 pounds of 4-chlorophenyl phenyl sulfone were dispersed on 49.5 poundsof Attaclay, a finely divided clay, together with a half pound ofDuponol 51, a higher aliphatic alcohol sulfate wetting agent. The finalcomposition provided a dry powder which, when placed with water, wet-tedreadily; the composition was sprayed on mite loci. Such compositions areusually applied at the rate of about two pounds per 100 gallons ofwater, although this can be varied between about one-half pound and fourpounds per 100 gallons. In place of Attaclay, one can use any othersuitable inert finely divided carrier such as pyrophyllite, diatomaceousearth, bentonite, volcanic ash, talc, lignocellulosic flour, sulfur, andmixtures of these. The concentration of 4-chlorophenyl phenyl sulfone inthe finished product can vary; generally it is desirable to utilize asmuch of the effective compound as is feasible and economical and theconcentration of the 4-chlorophenyl phenyl sulfone can be increased tothe order of 90% and up to 98%.

The 4-chlorophenyl phenyl sulfone can also be applied as a dust, beingmixed with any of the forementioned carriers, the wetting agent beingomitted. In this instance, the concentration of the 4-chlorophenylphenyl sulfone can vary over fairly wide limits, as between 1% and 50%.

The 4- chlorophenyl phenyl sulfone can also be applied as a liquiddispersed in water and one can make up a liquid concentrate bydissolving the 4-chlorophenyl phenyl sulfone in a suitable solvent andadding a wetting agent. Generally it is desirable that the concentrationof the 4- chlorophenyl phenyl sulfone be as high as its solubility in agiven solvent will permit. A typical composition includes 25% by weightof the 4-chlorophenyl phenyl sulfone, 10% of Triton X-l00, a wettingagent made by Rohm & Haas, 10% of acetone and the balance xylene or anequivalent solvent such as a petroleum fraction known as Socal 3. The4-chlorophenyl phenyl sulfone is soluble to a limited extent in the lessexpensive solvents and it is therefore desirable to add a small amountof a mutual solubilizing agent such as acetone.

The orthoand meta-isomers of the aforementioned 4- chlorophenyl phenylsulfone and his (4-chlorophenyl) sulfone were completely ineffectivewhen tested under the same conditions with the 4-chlorophenyl phenylsulfone and which killed all ova and active mite forms.

When 4-bromophenyl phenyl sulfone was substituted for 4-chlorophenylphenyl sulfone in the above tests, it exhibited a miticidaleffectiveness of the same order, but slightly less, than that of the4-chlorosulfone. Both compounds have valuable fungicidal properties andtheir application to plants is therefore also of value in this respectas well as against mites. The 4-bromophenyl phenyl sulfone can be madeby any of the foregoing procedures but utilizing the bromine compoundinstead of the corresponding chlorine compound, that is, by utilizing4-bromobenzene sulfonic acid instead of 4-chlorobenzene sulfonic acid inone case, and 4-bromobenzene instead of 4- chlorobenzene in the othercase.

The pesticidal properties of 4-chlorophenyl phenyl sulfone or4-bromophenyl phenyl sulfone are enhanced if they are applied inadmixture with diphenyl sulfone, with his (4-chlorophenyl) sulfone ormixtures of these compounds.

This enhanced activity is surprising from two standpoints. In the firstplace, diphenyl sulfone has only limited miticidal properties andbis(4-chlorophenyl) sulfone has no miticidal activity of its own, sothat one would not expect these compounds to exercise any substantialmiticidal activity when used together or with another compound. In thesecond place, the degree of enhancement is very great, and if onereplaces a portion of the 4-chlorophenyl phenyl sulfone with the lesseffective diphenyl sulfone, or bis(4-chlorophenyl) sulfone, or mixturesof these, the resulting composition is even more effective than the puremono halogenated sulfone.

The insecticidal activity of various mixtures of these compounds is alsosurprising, since the three sulfone compounds have only an insignficantinsecticidal effect when used alone, yet, when combined as will beexplained, they comprise an effective insecticide.

The above described phenomenon is a manifestation of synergism,activation, or both, as will now be explained:'

Synergism between toxicants has been defined by Wadley (see U. S. Bureauof Entomology and Plant Quarantine ET Series, Numbers 223 and 275) as ajoint action of two materials such that the total efiect is greater thanthe sum of the two efiects when each material is used alone; thisdefinition may be expanded to include three or more toxicants which actjointly :to produce a toxic effect greater than the sum of theiradditive efiects.

The foregoing definition of synergism is limited to toxicants thatproduce some effect when used alone. A mixture containing one toxic andone non-toxic compound but which exhibits a similar phenomenon isreferred to as an activating mixture, the phenomenon being referred toas activation.

The existence of synergism or activation can be determinedexperimentally by comparing the effect of a mixture of compounds withthe etfect expected from the sum of the separate toxic eifects of thecompounds when each is used alone. For example, if compound A has atoxicity of 1 unit and compound B has a toxicity of 2 units, a 1:1mixture of these compounds would be expected to have a toxicity of 1 /2units. If, however, the toxicity of the mixture is appreciably greaterthan 1 /2 units, synergism has been demonstrated. As another example, ifcompound A has a toxicity of 1 unit and compound C has a toxicity of 0,a 1:1 mixture of these compounds would be expected to have a toxicity of/2 unit. If, however, the mixture has a toxicity appreciably greaterthan /2. unit, activation has been demonstrated.

The phenomenon of synergism or activation is not limited to a twocomponent mixture and one may encounter the following typical example:If compound A has a toxicity of 1 unit and compound B has a toxicity of2 units and compound C has a toxicity of 0, a 1:1:1 mixture of thesecompounds would be expected to have a toxicity of 1 unit. If, however,this mixture has a toxicity greater than 1 unit, synergism, activation,or both, have been demonstrated.

Where synergism or activation are obvious and very pronounced, it iscustomary to express toxicity as the percentage kill of the organismafforded by the toxicant at a given dosage in demonstrating theexistence of the phenomena. In such cases, an examination of thepercentage mortality data of the individual components and of themixtures of the components will provide satisfactory proof of thepresence of synergism, activation or, possibly both of these. For thedetermination of synergism or activation, where these phenomena are realbut not obvious, it is customary to express toxicity on terms of thedosage required to kill 50% of the organisms; this expression oftoxicity is commonly referred to as the lethal dosage-50%, LD50.

Wadley (see U. S. Bureau of Entomology and Plant Quarantine ET Series,Numbers 223 and 275) has outlined an accepted procedure for thedetermination of synergism in a two component mixture which consists ofcomparing the actual LD50 value of a mixture of the two components withthe LD50 value expected from the additive effects of the components inthe mixture. This procedure can be expanded for use in three or morecomponent synergistic or activated mixtures.

The following examples prove that mixtures consisting of all three orany two of the components under consideration provide synergistic oractivated mixtures.

Example 1.-Showing the action of 4-chlorophenyl phenyl sulfone, bis(4-chlorophenyl) sulfone and diphenyl. sulfone on the two-spotted mite,Tetranychus bimaculatus Harvey:

Sprays were prepared by dissolving the component or mixture ofcomponents in acetone at a concentration of 2.5 grams per 100milliliters. The solution was added to water in the amount necessary tofurnish the desired concentration in the final spray. The followingadjuvants, at the concentrations shown, were used in the spray tofacilitate dispersability and wetting: methyl cellulose at 0.005% andVatsol OT (A higher alcohol ester of sodium sulfosnccinic acid) at0.015%.

Seedling pinto bean plants free of mites were sprayed thoroughly withaqueous sprays containing the following concentrations of each componentor mixture: 0.10%, 0.08%, 0.06%, 0.04% and 0.02%. After the plants haddried tho-roughly, each was infested uniformly with all postembryonicstages of the two-spotted mite. The plants were then set aside in thegreenhouse for seven days, after which time they were carefully examinedand the numbers of dead and live eggs and postembryonic forms recorded.

Dosage mortality curves were calculated for 4-chlorophenyl phenylsulfone and for diphenyl sulfone using the method outlined by Bliss(Annals of Applied Biology, volume 26, pp. 813-821). Sincebis(4-chlo'rophenyl) sulfone was not toxic it was impossible tocalculate a dosage mortality curve and therefore, an LD-SO value ofinfinity was assigned to the compound in accordance with acceptedstatistical procedure.

Dosage mortality data for each mixture of compounds was evaluated by themethod outlined by Wadley (U. S. Bureau of Entomology and PlantQuarantine ET Series Numbers 223 and 275).

From the procedure outlined in the above mentioned publication ET 223 itwas found that diphenyl sulfone showed an equivalence of 0.2151 withrespect to 4-chlorophenyl phenyl sulfone. In other words diphenylsulfone was found to be 0.2151 times as toxic as 4-chlorophenyl phenylsulfone. This equivalence was obtained by dividing the LD-50 of4-chlorophenyl phenyl sulfone (.0416) by the LD-50 of diphenyl sulfone(0.1934).

Each concentration of the mixture was then transformed into terms of4-chlorophenyl phenyl sulfone as outlined by Wadley (see Table 1, ET223). These are termed the 4-chlorophenyl phenyl sulfone equivalents.

The. 4-chlorophenyl phenyl sulfone equivalent is simply the dosage of4-chlorophenyl phenyl sulfone that would produce the same percentagemortality as the corresponding dosage of the mixture if the effects ofthe two components were only additive. Therefore, the mortality producedby the equivalent dosage represents that which would be expected if nosynergism occurs. If synergism does occur the mortality will be higherthan expected for each dosage.

In Table I, actual LD-50 values for 4-chlorophenyl phenyl sulfone (A)diphenyl sulfone (B) and bis(4-chlorophenyl) sulfone (C) are given.

In calculating actual LD-SO values for the mixture containing 1 part ofA and 1 part of B the dosages were transformed to equivalents in termsof 4-chlorophenyl phenyl sulfone. The actual LD-50 value of .0252 isconsiderably lower than the expected value of .0416. In this case theactual toxicity is 65 percent higher than would. be expected if thecomponents of the mixture produced only additive effects. The mixturetherefore, is unquestionably synergistic.

In the mixture containing 1 part of A and 1 part of C the same procedurewas followed. The only difference lies in the fact that C contributesnothing to the toxicity and contributes nothing toward the equivalentdosage.

Since the LD-SO for the actual toxicity of the mixture is .0194 and theexpected toxicity is .0416, it is obvious. that the actual toxicity ofthe mixture is 114 percent greater than would be expected from additiveeffects.

The mixture containing 1 part A, 1 part B and 1 part C has. been treatedin exactly the same manner. From an examination of the actual andexpected LD50 values it is obvious that the mixture is 151% more toxicthan can be accounted for by simple additive effects. This threecomponent mixture is therefore, unquestionably synergistic.

Since the toxicity is greater than that expected in each.

case, the existence of synergism is demonstrated in the mixture of A andB. Since bis(4-chlorophenyl) sulfone;

alone was ineffective under the conditions" of this test, the increasedactivity in the case of mixtures A--C and BC, is considered activation.Mixtures A-B-C may include both synergism and activation, but the extentof each is left undetermined for the overall result is alone consideredimportant at this time.

Example 2.Showing the interaction of 4-chlorophenyl phenyl sulfone,bis(4-chlorophenyl) sulfone and diphenyl sulfone on the bean aphid,Aphis fabae Scop:

Broad bean plants heavily infested with bean aphid were sprayedthoroughly with a spray containing 0.5% of each component or eachmixture. The spray was prepared as described in Example 1 except thatonly a.

concentration of 0.5% was employed. After spraying, the plants wereplaced in the greenhouse for 24' hours when a careful examination of theplants was made and the number of live and dead aphids recorded.

The percentage mortality afforded by' a component or component mixtureat the concentration of 0.5% is considered to furnish a satisfactoryevaluation of synergism in the mixture of these compounds, in view ofthe very pronounced increase in activity of the mixtures over thatafforded by separate components.

The essential data are presented in Table II.

In the above, the last mixture, that containing 74% A, 14% B and 12% C,is referred to as technical 4-chlorophenyl phenyl sulfone.

It will be noted that the mortality was greater in every case when amixture was employed.

The mixed sulfones, in any proportions, are solids at ordinarytemperatures. 4-chlorophenyl phenyl sulfone, diphenyl sulfone andbis(4-chlorophenyl) sulfone are miscible in all proportions when meltedwith each other to provide any two or three component mixtures. As isshown in the included data, the mixtures have been tested over a widerange of ratios and each of the mixtures exhibits superior utility ascompared to any single component. The ratio of various components to oneanother is not critical and all mixtures of diphenyl sulfone, bis(4-chlorophenyl) sulfone and 4-chlorophenyl phenyl sulfone, which providestwo or three component mixtures, exhibit a synergistic or activationefiect with respect to a single component.

To demonstrate the wide range of concentrations of the variousingredients which may be used, the following are set forth:

Example 3.--Acetone solutions of bis(4-chlorophenyl) sulfone and4-chlorophcnyl phenyl sulfone at varying ratios were added to water,together with a suitable wetting and spreading agent, and sprayed ontopinto bean plants heavily infested with two-spotted mite eggs(Tetranychlls bimaculatus Harvey). The concentration of 4-chlorophenylphenyl sulfone was held constant at 0.03% and the amount ofbis(4-chlorophenyl) sulfone was varied from 4.8% to 16.7% of the Weightof the 4- chlorophenyl phenyl sulfone. The percentage of mortalityincrease (see Table III) resulting from the addition of thebis(4-chlorophenyl) sulfone represents the efiect of its activation on4-chlorophenyl phenyl sulfone; activation alone is considered involvedsince, under the conditions of this test, bis(4-chlorophenyl) sulfonewas Thus, the addition of activator B to toxicant A, increases thetoxicity of the toxicant from 52% mortality to 92.1% mortality.

Example 4.--To explore the range of ratios over which 4-chlorophenylphenyl sulfone and diphenyl sulfone exhibit synergistic activity,wettable powders containing various ratios of these two compounds wereprepared according to the following procedure:

Weighed quantities of diphenyl sulfone and 4-chlorophenyl phenyl sulfonewere fused together and the mixture allowed to cool. The mixture Wasthen diluted by adding by weight of Attaclay and the resulting mixturewas ground in an air mill, of the type disclosed in the Kidwell Patent2,219,011. To the ground mixture was then added of Duponol 51, asulfated higher aliphatic alcohol wetting agent, to produce an easilywettable powder.

Varying concentrations of these preparations in water were then sprayedonto uninfested pinto bean plants. After the residue had driedthoroughly, the plants were infested uniformly with all postembryonicstages of the two-spotted mite, T etranychus bimaculazus Harvey. Theplants were then set aside for seven days in the greenhouse, after whichtime they were examined for dead and live mites.

The percentage mortality data were treated in an identical manner tothat described in Example I. The essential data, showing synergisticactivity in these mixtures, are presented in Table IV.

From these data, it is obvious that even the relatively small quantityof 2% diphenyl sulfone exerts a pronounced efiect on the toxicity of4-chlorophenyl phenyl sulfone. This effect is greatly increased athigher concentrations of the diphenyl sulfone.

It is preferred to operate within the range of from 2% to 98% of eitherdiphenyl sulfone or bis(4-chlorophenyl) sulfone or mixtures thereof withfrom 98% to 2% of 4-chlorophenyl phenyl sulfone and from about 2%98% ofdiphenyl sulfone with about 98 %2% of bis(4-chlorophenyl) sulfone. If athree component mixture is used, it is preferred that none of thecomponents be present in a concentration of less than 2%. A particularlygood two component mixture consists of about 25% diphenyl sulfone andabout 75% 4-chlorophenyl phenyl sulfone. A particularly good threecomponent mixture is the aforementioned technical 4-chlorophenyl phenylsulfone which consists of 74% 4-chlorophenyl phenyl sulfone, 14%diphenyl sulfone and 12% bis(4-chlorophenyl) sulfone. The invention isnot limited to these particular ratios, since any ratio may be used toadvantage as compared to one of the components.

The above demonstrations of synergism have been confirmed by fieldapplications.

Example 5.Two plots of physically adjacent apple trees heavily infestedwith the European red mite, Paratetranychus pilosus, C and F, weresprayed with two diiferent suspensions made with a 50% wettable powder,each suspension containing 0.12% of one of the toxicants. In one case,the toxicant was 4-chlorophenyl phenyl sulfone, while in the other, thetoxicant consisted of a mixture containing 5.4 parts by weight4-chlorophenyl phenyl sulfone and one part of diphenyl sulfone. With4-chlorophenyl phenyl sulfone, the control lasted twenty days, that is,the trees were mite-free for this period while with the mixturecontaining the two components, the trees were mite-free for sixty-sixdays. The trees in each plot were closely adjacent and were subject tothe same climatic conditions, wind and the like.

Example 6.A spray containing 0.12% of each of the following componentswas sprayed onto prune trees that were heavily infested with eggs andfirst instar forms of the clover mite, Bryobia praetiosa Koch. Afterseven days an examination of the twigs was made and the numbers of livemites were recorded.

Pretreatment counts showed that an average of approximately fifteen livemite individuals were present on each twig. At the end of seven days thenumbers of individual live mites per twig was determined by carefulexamination. These values and the percentage control are presented inTable V.

Table V No. ctr Mites P t per Wig ercen Material (0.12% 00110.) 7 daysafter Control Spraying 4-chlorophenyl phenyl sulfone 1. 90. 0 1:1Mixture, 4-ehlorophenyl phenyl sultone and diphenyl sulione 0. 4 97. 3Mixture of 74% 4-chlorophenyl phenyl sulfone,

14% diphenyl sulfone, 12% bis(4-chlorophenyl) sulfone 0. 4 97. 3

The above mentioned co-pending patent application Serial No. 105,273,July 16, 1949, and of which this is a continuation-in-part, and in thepresent application I have disclosed a process of making 4-chlorophenylphenyl sulfone by the reaction of benzene sulfonic acid andmonochlorobenzene, or by the reaction of p-chlorobenzene sulfonic acidand benzene. By selection of reaction conditions, one can obtain fromthis process a mixture containing about 70% 4-chlorophenyl phenylsulfone, 13% diphenyl sulfone, 11% bis(4-chlorophenyl) sulfone, 3%3-chlorophenyl phenyl sulfone, and 3% IZ-chlorophenyl phenyl sulfone.Based on the first three components, which form the effective portion ofthe mixture, the effective ingredients are present in approximately thefollowing proportions: 74% 4-chlorophenyl phenyl sulfone, 14% diphenylsulfone, and 12% bis(4-chlorophenyl) sulfone; this is technical4-chlorophenyl phenyl sulfone. This material is more efiective againstmites than 4-chlorophenyl phenyl sulfone, as is shown in the following:

Example 7.-At Winchester, Virginia, 50% wettable powder formulations of4-chlorophenyl phenyl sulfone and technical 4-chlorophenyl phenylsulfone were compared in an apple orchard heavily infested with a mixedpopulation of the European red mite and an undetermined species of mitebelonging to the genus T etranychus.

These two materials were applied thoroughly in sprays containingrespectively one pound per 100 gallons of each toxicant. The populationdensity of mites on the trees was determined at intervals followingapplication. The degree of control is expressed as the percentagereduction in mite density in the treated plots in comparison with themite density in a control plot.

The percentage control afforded by each material is presented in TableVI.

Example 8.-In a similar experiment at the same locality (see Example 7)on apple trees heavily infested with both the European red mite and anunidentified species of mite belonging to the genus Tetranychus,comparable results were obtained. Data obtained in this experiment arepresented in Table VII.

Table VI] Percentage Reduction in Mite Density following Treat- Materialin Spray ment after- (1 lb. per gals.)

3 days 1 week 2 weeks 4-ehlorophenyl phenyl sulfone 41. 4 46. 3 78. 8Technical 4-chlorophenyl phenyl sulfone 80. 3 83. 2 86. 3

The following show that the mixture defined above as technical4-chlorophenyl phenyl sulfone is an effective insecticide. In eachinstance the treated crop consisted of Valencia orange trees and theinsect pest was the black scale, Sassetia olea Bern. In these, theaverage number of scale was observed on 20 leaves or 10 twigs before andafter spraying. The technical 4-chlorophenyl phenyl sulfone was used inthe form of a 50% wettable powder (see Example 4 for the manner ofmaking this wettable powder), and is identified in each case as R-242,50% W. P.; the powder contained 50% by weight of R-242, the material ofExample 8, and prepared as is' taught in my aforementioned co-pendingapplication Serial No. 105,273.

Example 9.--The eifect of R-242, 50% W. P., was compared with that ofthe well-known insecticide, Parathion, in a usual composition forapplication of this material; Parathion is 0,0,diethyl O-p-nitrophenylthiophosphate. Counts were made of the scale population before the testand three months thereafter. The trees were sprayed with conventionalhigh pressure equipment at the rate of 21 gallons per tree. The resultsobtained are presented in Table VIII.

Example 10.--R242 may be combined with Parathion and the following TableIX compares the results obtained when R-242 is used alone or incombination. The trees were sprayed with 25 to 30 gallons of theindicated spray formulation per tree and'scale counts were made aboutten weeks later.

Table IX Average NAverJage f NllBllilbtig of um er ac Material 2 3 63 S1131:1031: icale on 20 ca e 2 ays 1 eaves per gamms Prior to Tree 10Spraying Weeks after Spraying Light medium oil emulsified. 1% gaL. 21. 30. 6 Parathion, 25% WP 11b 17.3 7. 8 Parathion, 25% WP L 1% lbs"--. 14.35. 4 Parathion, 25% WP 2 lbs 22. 3 O. 8 Parathion, 25% WI... 1 lb 39 0 1R-242, 50% WP Parathion, 25% WP 15 4 1 0 11-242 50% WP.- Parathion, 25%WP 18 7 1 0 11-242, 50% WP... Kerosene Parathion 25% WP 25. 3 43. 4 BASI Kerosene Parathion, 25% WP 20. 7 31. 2 BAS Kerosene Iarathion, 25% WP"16. 6 ll. 0 BAS lrgeroislelne .2. 7. if ara ion, 5 a 11-242, 50% WP 30.0 2. 2 BAS gerotslelne. fli

ara ion, 25 0 11-242, 50% WP. 3 6 BAS Kerosene Parathion, 25% WP 10 0 012-242, 50% WP BAS 1 Wettable powder. a Blood albumen spreader.

The compositions of the present invention can be applied in any desiredmanner such as an aqueous spray, as an aerosol, as a dust, an oilsolution, or an ointment. When applied as an aqueous spray, the sulfonecomponent of the spray should be present in a total concentration offrom 0.01% to 1.0%, usually about 0.125% to 0.25% by weight. Whenapplied as a dust, the sulfone content should be present in aconcentration of from 1% to 50% by weight in a suitable inert carrier,usually about 5%. The mixtures are not difficult to compound and one canemploy the mixtures in any of the carrier compositions utilizedheretofore with known acaricides or insecticides.

Example .I1.As illustrative of compositions which can be effectiveagainst mites and insects, the following are set forth:

About 35 pounds of 4-chlorophenyl phenyl sulfone was melted with 15pounds of diphenyl sulfone and the melt was allowed to cool andsolidify, whereupon it was ground in an air mill of the Kidwell patenttype. The ground mixture was dispersed by dry mixing on 49.5 pounds ofAttaclay, a finely divided clay, together with one-half pound of Duponol51, a sulfated higher aliphatic alcohol wetting agent. The finalcomposition provided a dry powder which, when added to water, wettedreadily; the composition formed with suitable for spraying on acaricideand insect habitats. Such compositions are usually applied at the rateof two pounds per 100 gallons of water although this can be varied frombetween about one-half pound and four to twenty-five pounds per 100gallons of water. In place .of Attaclay, one can use any other suitableinert finely divided carrier such as diatomaceous earth, bentonite,volcanic ash, talc, lignocellulosic flour, sulfur, and mixtures ofthese. The concentration of the components in the finished product canvary; generally it is desirable to utilize as much of the effectivecomponent as is feasible and economical and the concentration of thecomponents can be increased to the order of 90% and even up to 98%.

Example 12.-The effect of R 242 50% W. P. (made in accordance withExample 4) on the hog louse, Haematopinus suis (Linn.).

A group of swine that were heavily infested with lice were sprayedthoroughly with an aqueous suspension of the above mentioned material ata concentration of three pounds per gallons. After three days theanimals were examined thoroughly, and no live lice could be found. Atthe end of ten days the swine were examined again and were still freefrom lice. Unsprayed swine from the same herd remained heavily infestedduring the course of this experiment.

Example 13.The effect of R-242 10% dust on the Pacific Coast tick,Dermacentor occidentalis Neum.

A group of dogs that were heavily infested with ticks were dustedthoroughly with dust containing 10% R-242 and the balance an inertcarrier. The dogs were examined at the end of 24 hours and no live tickscould be found. The dogs were then permitted to inhabit a tickinfestedarea for ten days, after which time they were again examined. Untreated,uninfested dogs were permitted to inhabit the same area for the sameperiod of time.

The untreated dogs became infested with ticks at an average rate ofabout 5 per day, while the dogs receiving the treatment of R-242 10%dust were uninfested at the end of the ten day exposure period.

Example 14.The effect of R-242 10% dust on the dog flea, Ctenocephalides canis (Curt.).

A group of dogs that were heavily infested with dog fleas were dustedthoroughly with the dust of Example 13. They were permitted to inhabitan area that was heavily infested with fleas. A thorough examination ofthe dogs was made at the end of two days and no live fleas could befound. At the end of ten daysthe dogs were also free from fleas.

Example 15.The effect of R-242 on canine mange mites, Sarcopres scabiei,var. cam's Gerlach.

A group of dogs that were heavily infested about the ears, eyes andrectum with mange were treated with a 0.2% solution of R-242 incottonseed oil. One week after application, the dogs had improved to thepoint of almost complete cure.

The mixed sulfone components can also be applied, after being mixed withany of the aforementioned carriers, as a dust, the wetting agent beingomitted if desired. In the case of dusts, the concentration of the mixedsulfone components can vary over fairly wide litnits, as between 1% and50% and even more. The mixed sulfone components can also be applied as aliquid dispersed in water and one can make up a liquid concentrate bydissolving the mixed sulfone components in a suitable solvent and addinga wetting agent; the sulfone components are soluble in hydrocarbonsolvents usually employed in such compositions as are applied to plantsand animals. Generally it is desirable that the concentration of themixed sulfones be as high as the solubility of the mixture in a givensolvent will permit. A typical composition includes 25% by weight of themixed sulfone, 10% of Triton X-lOO, an alkylated aryl poly-ether alcoholwetting agent made by Rohm & Haas, 10% of acetone and the balance xyleneor an equivalent solvent such as a petroleum fraction known to the tradeas Socal 3. In many cases it is advisable to add a small amount of amutual solubilizing agent such as acetone to enable the less expensivesolvents such as petroleum fractions to be used.

Any of the two or three component mixtures described can be formulatedin the manner of the two preceding paragraphs.

The mixed sulfones have valuable fungicidal properties and theirapplication to plants and animals is therefore also of value in thisrespect, as well as against mites and insects.

In place of 4-chlor0phenyl phenyl sulfone one can use 4-bromophenylphenyl sulfone with practically equal utility although this lattercompound is more expensive to manufacture.

I claim:

1. The method of killing arthropod pests comprising applying to a pesthabitat a mixture containing a compound selected from group 1 and acompound selected from group 2 wherein group 1 consists of4-chlor0phenyl phenyl sulfone, 4-bromophenyl phenyl sulfone and mixturesthereof, and group 2 consists of diphenyl sulfone, bis(4-chlorophenyl)sulfone and mixtures thereof.

2. The method of killing arthropod pests comprising applying to a pesthabitat diphenyl sulfone and a material selected from the groupconsisting of 4-chlorophenyl phenyl sulfone and 4-bromophenyl phenylsulfone.

3. The method of killing arthropod pests comprising applying to a pesthabitat a mixture containing bis(4- chlorophenyl) sulfone and a materialselected from the group consisting of 4-chlorophenyl phenyl sulfone and4- bromophenyl phenyl sulfone.

4. The method of killing arthropod pests comprising applying to a pesthabitat a mixture consisting of diphenyl sulfone, bis(4-chlorophenyl)sulfone and a material selected from the group consisting of4-chlorophenyl phenyl sulfone and 4-bromophenyl phenyl sulfone.

5. A composition effective against arthropod pests containing an inertinsecticidal adjuvant as a carrier and a mixture containing a compoundselected from group 1 and a compound selected from group 2 wherein group1 consists of 4-chlorophenyl phenyl sulfone, 4-bromophenyl phenylsulfone and mixtures thereof, and group 2 consists of diphenyl sulfone,bis(4-chlorophenyl) sulfone and mixtures thereof.

6. The composition of claim 5 in which the mixture is in the form of apowder containing a finely divided inert solid carrier.

7. The composition of claim 5 in which the carrier consists of water andthe materials are dispersed therein.

8. The composition of claim 5 wherein each member is present in thequantity of at least 2% by weight of the mixture.

9. A composition of matter efiective against arthropod pests containingan inert insecticidal adjuvant as a carrier and as an efiectiveingredient a mixture of diphenyl sul- 14 tone and a material selectedfrom the group consisting of 4-chlorophenyl phenyl sulfone and4-bromophenyl phenyl sulfone.

10. A composition of matter efiective against arthropod pests containingas an effective ingredient a mixture of bis(4-chlorophenyl) sulfone anda material selected from the group consisting of 4-chlorophenyl phenylsulfone and 4-bromophenyl phenyl sulfone.

11. A composition of matter effective against arthropod pests containingan inert insecticidal adjuvant and as an effective ingredient a mixtureof bis(4-chlorophenyl) sulfone, diphenyl sulfone and a material selectedfrom the group consisting of 4-chlorophenyl phenyl sulfone and 4-bromophenyl phenyl sulfone.

12. A composition of matter effective against arthropod pests containingan inert insecticidal adjuvant as a carrier and as an efiectiveingredient about 74% 4-chlorophenyl phenyl sulfone, 14% diphenyl sulfoneand 12% bis(4-chlorophenyl) sulfone.

References Cited in the file of this patent UNITED STATES PATENTS2,148,928 de Meuron Feb. 28, 1939 2,224,964 Huismann Dec. 17, 1940FOREIGN PATENTS 220,406 Switzerland July 1, 1942 940,916 France Dec. 28,1948 OTHER REFERENCES Roark et al.: U. S. D. A. Bur, of But. and PlantQuar. E-344, p. 29, May 1935.

Metcalf: Journal Economic Entomology, vol. 41, No. 6, December 1948, pp.875 to 882 (see p. 878).

Questel et al.: U. S. D. A. Bur. of But. and Plant Quar, Bull. E-557,entitled Laboratory and Field Tests of Toxicity of Some OrganicCompounds to the European Corn Borer, December 1941, pp. 1-17 (see p.11).

Lauger et al.: Helv. Chim. Acta, vol. 27, June 1944, pp. 896 to 908.

1. THE METHOD OF KILLING ARTHROPOD PESTS COMPRISING APPLYING TO A PESTHABITAT A MIXTURE CONTAINING A COMPOUND SELECTED FROM GROUP 1 AND ACOMPOUND SELECTED FROM GROUP 2 WHEREIN 1 CONSISTS OF 4-CHLOROPHENYLPHENYL SULFONE, 4-BROMOPHENYL PHENYL SULFONE AND MIXTURES THEREOF, ANDGROUP 2 CONSISTS OF DIPHENYL SULFONE, BIS(4-CHLOROPHENYL) SULFONE ANDMIXTURES THEREOF.